The impact of porous medium heterogeneity on the thermal feedback of open-loop shallow geothermal systems

Dato, Mariaines Di; D'Angelo, Claudia; Casasso, Alessandro; Zarlenga, Antonio

doi:10.1016/j.jhydrol.2021.127205

Cited by 12 publications

(14 citation statements)

References 86 publications

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“…The high sensitivity degrees of K s and Sy s in both models show that the sand layer has a strong effect on the spring hydrographs, which reflects the restrictive function of the covering porous layer on system discharge behaviours. Many studies have revealed the significant effect of heterogeneous porous media on fluid flow and solute transport (Di Dato et al, 2022; Tartakovsky et al, 2017). As a result, more field data should be collected in the porous layer of karst systems, which helps account for spring hydrologic behaviours and water storage variation in karst aquifers.…”

Section: Resultsmentioning

confidence: 99%

Identification of karst spring hydrographs using laboratory and numerical simulations considering combined discrete‐continuum approaches

Chen,

Shu,

Lian

et al. 2023

Hydrological Processes

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The quantitative analysis of karst spring hydrographs aids in characterizing the hydrodynamic properties of aquifer systems. However, the relationships between spring hydrographs and hydrologic functions of different media lack in‐depth research. This study detected the rainfall‐discharge processes of covered karst systems using two combined discrete‐continuum models (a coupled continuum‐pipe model and a hybrid model) developed based on laboratory experiments. An improved exponential function was used to decompose spring recession hydrographs with a great performance, and the results indicate that the slow drainage controlled by the porous medium dominates the whole recession process. There is a shift in the contribution of the matrix to karst discharge systems with the increase of its hydraulic conductivity. Although spring hydrographs have a great dependency on the hydraulic process of fracture networks, the variation in permeability of the matrix significantly changes the storage capacity of fractured rocks and spring discharge behaviours. The changing process of water storage rate of the matrix and fractures with spring hydrographs reveals three stages: a period of steep rise and fall, a period with slight fluctuations, and a gentle descent stage. The parameter sensitivity analysis in both models shows that the covering porous layer has a strong effect on the patterns of karst spring hydrographs, and the specific yield is more sensitive than hydraulic conductivity. While these simulations were conducted at the laboratory scale, the findings provide insights into practical applications of spring protection and water resources management.

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Section: Resultsmentioning

confidence: 99%

Identification of karst spring hydrographs using laboratory and numerical simulations considering combined discrete‐continuum approaches

Chen,

Shu,

Lian

et al. 2023

Hydrological Processes

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“…TAZ plumes represent a potential anthropogenic source of pollution; they pose a risk to groundwater down-gradient users, and they also affect the sustainability of geothermal well systems. In addition, reinjected water has a different temperature than the undisturbed aquifer (i.e., colder when the plant operates in heating mode, and hotter when it operates in cooling mode), and returning that water to the abstraction well can present a major technical and design issue (i.e., the thermal feedback phenomenon) [7]. Avoiding adverse effects on adjacent geothermal systems through a TAZ produced in the subsurface prediction is required.…”

Section: Gwhp Systems: Technological Potential and Environmental Limitsmentioning

confidence: 99%

“…The thermal exchange takes place directly with the extracted groundwater [5,6]. These systems were designed to take advantage of the available heat in the shallow subsurface by extracting water from a well or surface water source [7][8][9]. Closed-loop systems (e.g., borehole heat exchangers (BHEs), energy piles) take advantage of the subsurface resource, defined by a specific local geothermal gradient value.…”

Section: Introductionmentioning

confidence: 99%

A Review of Groundwater Heat Pump Systems in the Italian Framework: Technological Potential and Environmental Limits

et al. 2023

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For new buildings in densely urbanised cities, groundwater heat pump systems (GWHPs) represent a concrete, effective solution for decarbonising existing energy systems. Environmental factors must be considered to limit the GWHP system’s impact on the subsurface. Particular attention must be given to the long-term sustainability of groundwater abstraction modalities and the development of a thermally affected zone around re-injection wells. Simplified solutions and numerical models have been applied to predict subsurface heat transport mechanisms; these simulations allow researchers to consider site-specific geological conditions, transient heat and groundwater flow regimes, and anisotropies in the subsurface media. This paper presents a comprehensive overview of the current research on GWHPs and discusses the benefits and limitations of their diffusion in Italy. The sources used provide information on and examples of the correct methodological approaches for depicting the induced variations while avoiding the overestimation or underestimation of the impact that GWHPs have on exploited aquifers.

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“…Alberti et al [25] consider two types of ground source heat pumps, fitting the numerical ground response with analytical solutions and comparing the two models; the effect of the grout material was assessed in terms of exchanged energy and temperature distribution in the subsoil. In the simulation process, the same parameters obtained different results in different simulation processes (Di Dato et al [26]); the interaction between heterogeneity and some thermal hydrogeological parameters and engineering parameters is studied in this process. With thermal break time and recirculation ratio as the main design parameters, thermal break time alone will lead to the conclusion of system error.…”

Section: Introductionmentioning

confidence: 99%

A Multiphysics Simulation Study of the Thermomechanical Coupling Response of Energy Piles

Xu,

Wang,

Meng

et al. 2024

Buildings

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The global demand for energy is on the rise, accompanied by increasing requirements for low-carbon environmental protection. In recent years, China’s “double carbon action” initiative has brought about new development opportunities across various sectors. The concept of energy pile foundation aims to harness geothermal energy, aligning well with green, low-carbon, and sustainable development principles, thus offering extensive application prospects in engineering. Drawing from existing research globally, this paper delves into four key aspects impacting the thermodynamic properties of energy piles: the design of buried pipes, pile structure, heat storage materials within the pipe core, and soil treatment around the pile using carbon fiber urease mineralization. Leveraging the innovative mineralization technique known as urease-induced carbonate mineralization precipitation (EICP), this study employs COMSOL Multiphysics simulation software to analyze heat transfer dynamics and establish twelve sets of numerical models for energy piles. The buried pipe design encompasses two types, U-shaped and spiral, while the pile structure includes concrete solid energy piles and tubular energy piles. Soil conditions around the pile are classified into undisturbed sand and carbon fiber-infused EICP mineralized sand. Different inner core heat storage materials such as air, water, unaltered sand, and carbon fiber-based EICP mineralized sand are examined within tubular piles. Key findings indicate that spiral buried pipes outperform U-shaped ones, especially when filled with liquid thermal energy storage (TES) materials, enhancing temperature control of energy piles. The carbon fiber urease mineralization technique significantly improves heat exchange between energy piles and surrounding soil, reducing soil porosity to 4.9%. With a carbon fiber content of 1.2%, the ultimate compressive strength reaches 1419.4 kPa. Tubular energy piles mitigate pile stress during summer temperature fluctuations. Pile stress distribution varies under load and temperature stresses, with downward and upward friction observed at different points along the pile length. Overall, this research underscores the efficacy of energy pile technologies in optimizing energy efficiency while aligning with sustainable development goals.

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The impact of porous medium heterogeneity on the thermal feedback of open-loop shallow geothermal systems

Cited by 12 publications

References 86 publications

Identification of karst spring hydrographs using laboratory and numerical simulations considering combined discrete‐continuum approaches

Identification of karst spring hydrographs using laboratory and numerical simulations considering combined discrete‐continuum approaches

A Review of Groundwater Heat Pump Systems in the Italian Framework: Technological Potential and Environmental Limits

A Multiphysics Simulation Study of the Thermomechanical Coupling Response of Energy Piles

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